Wednesday, January 16, 2013

Can A-theorists accept the Principle of Sufficient Reason?

According to the A-theory (at least on the versions I am interested in here), it's an objective but temporally changing (and hence contingent) fact that the year 2013 is present (i.e., lit up by the spotlight, on the leading edge of the growing block, or the year containing all real events, depending on the version of the A-theory).

But why is 2013, instead of say 2012 or 10 billion BC, present? Note that our argument will work whether or not by "2013" we mean a rigid designator of a particular year or some sufficiently long definite description.

Well, the one answer I can think of leads to a regress: 2013 is present because last year 2012 was present. For then we ask why last year 2012 was present. And the answer is, presumably, that two years ago 2011 was present.

This regress is infinite or finite. If it's infinite, we have something unexplained—namely why all of these years happened when they did vis-a-vis the present, 2012 a year ago, 2011 two years ago, and so on.

If it's finite, we have something unexplained, namely why it was that N years ago it was the year 2013−N, where N is the age of the world.

Can we give a theistic answer? Let's suppose "2013−N" is a definite description like "the first year of time". So: Why was the first year of time N years ago? Answer: Because N years ago, God created time (or the universe). But now we have a new puzzle: Why did God create time N years ago (i.e., before the lit-up time, before the year containing all real events, or before the leading edge of the growing block) rather than, say, N−1 years ago? (Or maybe better: Why is it N years after God created time?) After all, this is a contingent fact. Last year, it wasn't true that God created time N years ago (i.e., before the lit-up time, etc.)—it was instead true that God created time N−1 years ago.

Let's try our regressive explanation again. For we could say that God created time N years ago, because a year ago it was the case that N−1 years ago God created time. But this regress is actuality a circularity. For if we apply this schema N times, we get to the explanation that N years ago it was the case that 0 years ago God created time. But that's just a fancy way of saying that N years ago God created time, which is what was to be explained. Oops.

Perhaps there is some other explanation. Maybe God created time N years ago because N years ago was the first year of time, and God could only create time in the first year of time. But now we have a new question: Why is it that the first year of time was N years ago? And we better not go down the road of saying that a year ago, the first year of time was N−1 years ago, as then we'll end up, in a finite number of steps, with the claim that N years ago, the first year of time was 0 years ago, which is just a fancy way of sayingt hat the first year of time was N years ago.

If I am right, then the A-theorist cannot explain why it's 2013. The B-theorist denies that there is any such objective fact, except for the trivial fact that at t0 it's 2013 which holds because of necessary truths about t0 and 2013.

Now perhaps a given presentist hasn't been convinced by the arguments for the Principle of Sufficient Reason. But nonetheless it counts against a theory that it posits contingent unexplained facts that a competitor does not.

30 comments:

Must someone who holds the B-Theory of time also be an eternalist? I'm just wondering, because it seems like any sort of causality or causal principle goes out the window on eternalism. No objective causes and effects, only correlations. But if we can't appeal to causality, the "illusory" causality simply becomes unexplained patterns.

The question of why God created the world at a particular time, rather than at some other time, doesn't seem any easier or harder for the B-Theorist, does it? It seems to me that the answer in both cases is: Libertarian free will. He created it then because He chose to.

As to the PSR and A-theory, I really don't see the problem. It had to be 2013 at SOME point, and so it's 2013 right now because this is as far as we've gotten. What am I missing here?

Michael: The B-theorist can take the Augustine route: if time has a beginning, times are defined relatively to the first moment of time, and so it's not possible for time to be created except at the first moment of time.

ozero91:

I think B-theory requires eternalism, but I don't see why there is no causation on eternalism.

Why is Augustine's answer unavailable to the A-theorist? Times are all defined relatively to the first moment in time, and therefore it's 2013, because a certain number of years have passed since that first moment... Again, I don't think the A-theorist has any more of a problem here than the B-theorist. If you can ask the A-theorist "why was the world created 14 billion years ago, instead of 15 billion?" you could ask the B-theorist "why does the 4-dimensional block begin at this point rather than some other point?". Do you see what I mean? It seems to me that "why is it now, now?" is a question that A- and B-theorists can both answer with something like Augustine's point.

And, as a side-point, it seems rather evident that Augustine had an A-theoretical viewpoint in mind when he made that answer, and so it should (if anything) be MORE at home in the A-theory than in the B-theory.

"Why has that particular number, rather than a smaller number or a greater number, passed since that first moment?"

Again, the same question can be asked of the B-theorist, only in terms of the space-time block. Why does it begin X number of years before now, rather than Y? The answer has to be Libertarian free will on God's part to create it when He did, coupled with the Augustinean point you made: We've only made it this far.

This all brings me back to my central problem with B-theory: The main motivation for this notion (which contradicts an intuition as basic as the one that tells us we have free will) is STR. And, since STR is superseded by GTR (and GTR entails a Universal reference frame, and that spatio-temporal warping is a dynamic feature of a progressing world), it follows that that main motivation is moot. Moreover, there are interpretations of STR which yield exactly the same empirical and mathematical consequences, but which are A-theoretical in nature. William Lane Craig has done a great deal of work on this topic, and he has concluded (along with others like Lawrence Sklar) that the view of STR which yields a B-theoretical worldview is verificationist in nature; and has no motivation in the absence of verificationism (which is a defunct, self-refuting philosophical position).

But an answer can be given to that, because "now" is just an indexical like "I". In fact, it's a necessary truth on my Augustinian B-theory that if time includes now, then now is X years after the beginning (just as it's a necessary truth on my essentiality of origins view that if I exist, then I am the child of such-and-such parents). So the only contingency to be explained is why time includes now. But that contingency is presumably to be explained by giving the sorts of reasons that God had to create time and to let the universe go on for such a long time.

Again, I really don't see why symmetrical answers aren't available to the A-theorist. Augustine's own view was that the "now" is just a knife edge that moves progressively into the future. The only real point is "now", and the contingent fact that "now" happens to be 2013 is explained by the fact that God chose freely to create the world X amount of time ago.

Eternalism is perfectly compatible with genuine causation. David Lewis doesn't do it that way, but you can't assume Lewis' entire Humean framework to criticize parts of his view that don't assume that Humean framework, and the B-theory doesn't assume the Humean framework. For genuine causation, one fact makes another true. Why couldn't that be true on a B-theory? Just because the events both exist at different times rather than only one existing or neither existing doesn't mean it's not real causation. I would think that causation would actually require both cause and effect to be real, in fact. So maybe it's presentism that has problems with causation.

There certainly are a number of other motivations one can have for the B-theory besides relativistic stuff. A list, no doubt partial:1. simplicity of theory2. divine omniscience and immutability3. divine omniscience and atemporality4. McTaggart-style arguments5. odd consequences for inductive reasoning on A-theory6. presentism and growing block don't fit with moral and other intuitions (why should we care about non-existent events?), while moving spotlight is unattractive7. the logical possibility of time travel8. similarities between "now" and indexicals like "I" and "here"

As for General Relativity, I think that approach doesn't work. It may be that the structure of the universe suggests a particular family of foliations that are close to one other. But I don't think there is much reason to think it suggests a particular unique foliation. I think these cosmological considerations are only going to give one something to a level of approximation, not a foliation uniquely defined locally.

I don't think that any of those reasons bring any warrant for the B-theory. Immutability and eternality need to be construed in a softer sense, as John Feinberg has argued in No One Like Him.

McTaggert's paradox does not touch presentism.

We do care about non-existent events, such as counterfactuals. It would be very disturbing to know that my closest family members would knife me in the back given the chance, for example. We need a theory of truth that does not commit us to truthmaker maximalism in any case.

Time travel and backward causation are, in my opinion, absolutely and unquestionably refuted by the bilking paradoxes of Antony Flew and Max Black. Presentism can explain why time travel is impossible. The B-theory has a much harder time explaining why these bilking paradoxes won't show up.

"Here" is reducible to "where I am right now" while "this" is reducible to "what I am specifying right now"

"Now", on the other hand is not reducible.

The B theory is also vulnerable to arguments against actual infinites. If the B-theory was true, then immortality would entail that there are an actual infinite number of events.

"Eternalism is perfectly compatible with genuine causation. David Lewis doesn't do it that way, but you can't assume Lewis' entire Humean framework to criticize parts of his view that don't assume that Humean framework, and the B-theory doesn't assume the Humean framework. For genuine causation, one fact makes another true. Why couldn't that be true on a B-theory? Just because the events both exist at different times rather than only one existing or neither existing doesn't mean it's not real causation. I would think that causation would actually require both cause and effect to be real, in fact. So maybe it's presentism that has problems with causation."

But does it makes sense to say that "different times" exist on the eternalist view? Can there be different times without a "progression" or "flow" of time? If you can show that change/causation (ice's potential to become water is actualized by heat energy) is compatible with the B-Theory, then I guess it is simpler. Do you or Pruss have any handy links about causation and eternalism? I'm no expert, but for now I'm not convinced (but willing to learn) that genuine change/causation is possible on an eternalist view, and it seems every unexplained regularity counts against the simplicity of eternalism. Or maybe we can just say that time does not exist on its own, but is dependent on change?

But in any case, "I" doesn't seem to be subject to a similar reduction.

The paradoxes only show that you can't have time travel in cases where causal loops could result. The following would be a bad argument against simultaneous causation: "If simultaneous causation were possible, then it would be possible for A to cause B while B causes A." Simultaneous causation is possible, but only in situations where circularity of causation doesn't result. Likewise, backwards causation is possible, but only in situations where circularity of causation doesn't result. And time travel is like backwards causation.

While we do care about counterfactuals, I think what we care most about is the dispositional bases of the counterfactuals. I care about the fact that so-and-so would stab in the back, because this fact indicates something about his character. Suppose (contrary to fact) that Molinism is true. Then occasionally, there will be counterfactuals of free will that come apart from character. Someone has a truly wonderful character, but in C would do wrong. This fact is one we shouldn't care about much, except insofar as it reveals the fact that his character is compatible with that action. Given Molinism, it seems very likely to me that for just about any person, there is some non-actual circumstance C in which that person would do something terrible to us, despite having a character strongly opposed to that. (After all, there are infinitely many non-actual circumstances...)

Moreover, we care about counterfactual events rather less than about actual. But that someone I love will be tortured, half-way around the world, in five minutes is no less significant to me than that this is happening now.

I know of only one good argument against an actual infinite, and this is the Grim Reaper argument. But it doesn't rule out all actual infinites, but only cases where infinitely many things are antecedent to one event.

B-theorists think of time as like space. (We are often criticized for this.) Now, simultaneous causation between things that are spread out in space seems possible. If time is like space, why should cross-time causation be a problem?

Remember Kant's wonderful example of how causation doesn't even require change. (Not that the B-theorist denies the existence of change.) We have a metal ball sitting eternally on a piece of felt. The ball eternally makes a depression in the felt. But neither the ball nor the felt ever changes.

Given enough time, anything that can happen will happen. Assuming infinite time then, I don't see any way to deny the eventuality of a bilking paradox save for also denying free will. Thus, if an individual is prevented from such paradoxes by an eternal declaration, then we can rescue B theory but only at the expense of our own liberty. This seems to me to be a high price to pay.

I'm curious to know why you think other arguments beside the Grim Reaper fail to refute the possibility of an actual infinite. Presumbably, if the universe itself is infinitely old and we accept contemporary descriptions of the quantum vacuum, then an infinite number of quantum events has preceded the last quantum event. Personally, I cannot comprehend how causal connections can even come about if they don't also terminate in an effect.

I don't think one can travel back in time in ways that allow interaction with things in one's causal history. So you can't go back to the past and shake hands with your great-great-grandfather, unless the system is set up so that the effects are guaranteed to peter out. Otherwise there will be a loop in causal dependence.

But nothing like this prevents one from time traveling to some area of the past that is causally isolated from one's causal history. Maybe this doesn't really count as backwards time travel. Maybe it does.

Here's a thought, although I might just be confusing myself here. The question, "Why is it that the first year of time was N years ago?" is the same as the question, "Why have N years elapsed since the first year of time?" If the A-theorist assumes a relational view of time, then can't this be answered with reference to the events that have occurred since the first year of time? And if she assumes a substantial view of time, then can't she answer this with reference to the cause of the elapsing of time since the first year if time?

"But what explains why X amount of time ago God chose freely to create, rather than X+1 or X-1?"

Free will. It was God's choice to create when He did. Moreover, on an A-theoretical (and, I would add, Agustinean) framework, time began at that moment, and every moment will take it's designation relative to distance from that first moment. It is a necessary truth that if N years elapse after the creative moment, it will be N years after the creative moment (tautologously). As such the only contingent fact to be explained is why you're asking the question today rather than on some other day (and that can be answered based on whatever influences happened to motivate you at this point).

I think Drew did a great job of listing the problems with B-theory. To the question of "why should we care about non-existent events?", an answer could be that the fact of their having happened in the past influences the shape of the present. Even the counter-factual knowledge that "if I did X, some destructive event Y would ensue" effects the present reality and my state of mind.

And, by the way, the knowledge that a loved one is going to be tortured or that they have been tortured is not NEARLY as painful or significant as the knowledge that they are at this moment being tortured. And this goes back to the objection on the basis of the Problem of Evil. If all events are equally real, eternally and unchanging, then evil is never really overcome. Events of great suffering are never actually surmounted; they just persist eternally at that point in time, even as moments of joy occur at other times.

I would also challenge the idea that B-theory is simpler. We have to invent a whole new vocabulary (or, at least, consistently modify our usual vocabulary) just to state day-to-day matters in B-theoretical terms. It is counter to the basic intuition of temporal becoming. And I would argue that that basic intuition is directly linked to (if not foundational to) the intuition of free will. Our intuition that we have free will is directly tied to the belief that the future is not set; that there is no "fact of the matter" as to what I will decide. Trying to have free will AND a "fact of the matter" about a future decision is what leads to nonsense theories like Molinism or to some form of Compatibilism. However, if temporal becoming is real, then our intuitive grasp of free will remains intact.

My friend Leo Mollica brought this point up to me a couple of weeks ago. Did he talk to you about it? If not then that just proves great minds think alike (i.e. you two!)

Anyway, could we say that the reason this time is the present one is because God willed it to be the present moment? On a Thomistic view God is continually creating or sustaining the world, so maybe this isn't far-fetched. As for why God willed 2013 to be the present moment, or why he willed 2013 to be the present moment *rather than another*, who knows? We can appeal to mystery and say that God in his infinite wisdom has a reason, though we cannot know it. It's not necessarily an ad hoc move to do this I don't think. I may very well be missing something though?

I ran a version of this argument by Josh Rasmussen some time ago. I can't remember what he said.

I like the answer that right now the 2013 world is actual because God right now wills the 2013 world to be actual. That was my suggestion in my response to Heath. If something like this is the only possible answer, then we have an argument that A-theory + PSR implies continual creation. And it's nice to have an argument for continual creation, even if the first premise of the argument is false.

We can fill this out as follows. The 2013 world has certain merits that, say, the 2012 and 2014 worlds don't. The 2013 world, for instance, includes my youngest daughter being three months old, a particularly cute and delightful age. No other year includes this distinctive good. Sure, other years include similar goods, such as my oldest daughter being three months old, but babies aren't fungible, and so those goods are incommensurable with this one.

So in light of all the goods that 2013 exhibits but that other years do not, God creates 2013. Why did he make the 2013 world now and not last year? Well, because last year he made the 2012 world, which has some other goods, such as my youngest daughter's being born, and next year he will make the 2014 world, which will include other goods that I do not yet know of.

This works best on presentism.

OK, but now why is it N years since the beginning? My suggested answer is: the 2013 world, along with its manifold distinctive merits, has an N-year-old cosmos in it. (There are multiple essentially similar formulations. It has in it a fact that it's N years from the beginning. Etc.) Whether having an N-year-old cosmos is itself one of the merits of the 2013 world or whether it just comes along for the ride, integrally connected with the other merits, doesn't seem to matter.

Objection: But isn't the reason that the 2013 world is now present that the 2012 world was present a year ago?

Response: Yes, that's one of the merits of the 2013 world, that it neatly follows up on a year-world that has just passed. But at the same time, one of the merits of the 2012 world was that it was the sort of year-world that would naturally be followed up by the a year-world with the merits of the 2013 one.

What are these year-worlds? Maybe worlds as abstract entities embodying an eternal point of view, and year-worlds as embodying the point of view of a particular year. Or maybe an instant-world is the collection of all propositions true at that instant, and a year-world is a collection of all the instant worlds over a year.

As much as I would like to endorse this Thomistic approach, I have to say that your tongue-in-cheek comment about how cute your daughter is now is indicative of the completely subjective kind of "goods" you're talking about. If it is *objectively* good that it be this year, then it should always be this year, unless all years are equally good for different reasons, in which case it should be all of them at once. This is just not a coherent way of looking at things on an A-theory. The A-theorist does much better to say that the Universe could only begin to exist at the first point in time (anything else is obviously incoherent), and that the only contingent fact is when the question is being asked. And there are factors that can be accounted for to explain why you asked this question now, rather than last year or next year. But having accounted for that, the entire problem dissolves. The world began at the first instant of time. And that wouldn't have been N years ago if you had just waited another year to ask the question. It would have been N+1 years ago. So, the contingent fact is the asking.

But, if they are equal goods, then how can God choose which to instantiate? awatkins69 said we'd need to appeal to mystery, but I think the situation is even worse than that. And all the mental gymnastics that we have to go through to justify "year-worlds" and their sequence of instantiation... all of it goes away on my approach.

The thing is: I favor A-theory, and I am a staunch proponent of the PSR (and a huge fan of your book on it, as well as your chapter in the Blackwell Companion). And I did encouter this sort of question in passing, about whether there was something amiss in combining A-theory with the PSR, but it almost instantly become obvious to me that time beginning at the first point in time is a necessary truth, and questions of distance between that point and "now" are contingent on when "now" is, which in turn is predicated entirely on when I ask the question.

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